SpringMVC框架使用
环境:
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idea开发
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jdk1.8
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tomcat8.5
非注解方式:
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新建maven工程
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pox.xml中导入依赖
<!-- 公共依赖--> <dependencies> <!-- https://mvnrepository.com/artifact/junit/junit 单元--> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.3.4</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api --> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.2</version> <scope>provided</scope> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet/jstl --> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok 方便pojo类--> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.12</version> <scope>provided</scope> </dependency> </dependencies>
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添加web支持
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在web.xml中注册DispatcherServlet
<!--配置SpringMVC的核心控制器:拦截所有的请求 在启动时加载文件,需要提前配置load-on-startup(避免在页面访问时才报错)--> <servlet> <servlet-name>dispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--加载配置文件:使用放在resources目录下,重新定义加载的路径--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext-mvc.xml</param-value> </init-param> <!--servlet启动的优先级--> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>dispatcherServlet</servlet-name> <!--拦截所有url为/开始的请求--> <url-pattern>/</url-pattern> </servlet-mapping> <!--项目启动的欢迎界面--> <welcome-file-list> <welcome-file>/jsp/index.jsp</welcome-file> </welcome-file-list>
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根据web.xml设置的配置文件路径,新建springmvc-servlet.xml(classpath是指经过编译之后classes的文件夹)
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!--SpringMVC不用注解方式:--> <!--handler映射器 --> <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/> <!--handler适配器--> <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/> <!--name:访问的映射路径,视图解析器--> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <!--前缀--> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> <bean id="/hello" class="fun.nsk666.controller.HelloController"/> </beans>
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在java文件夹中新建controller包,再新建controller
package fun.nsk666.controller; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.Controller; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * @Author: nsk * @Description: * @Date: create in 2021/3/29 20:35 */ //使用Controller的类,使用HttpServletRequest和HttpServletResponse接收数据, //使用ModelAndView对象发送数据和制定要跳转的页面 //向index.jsp跳转,并且再index.jsp接收msg,因为在springmvc-servlet.xml中配置试图解析器,所以setViewName只写index即可 public class HelloController implements Controller { public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception { ModelAndView modelAndView = new ModelAndView(); modelAndView.addObject("msg","hello,world"); modelAndView.setViewName("index"); return modelAndView; } }
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根据springmvc-servlet.xml中的试图解析器的路径,新建index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>$Title$</title> </head> <body> <!--接收传过来的msg--> ${msg} </body> </html>
注解方式
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前面步骤与非注解方式的1,2,3,4步骤一致
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在springmvc-servlet.xml中配置注解的方式使用springmvc
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!--使用注解方式--> <!--自动扫描包,让spring注解生效,由IOC容器统一管理 --> <context:component-scan base-package="fun.nsk666"/> <!--让springMVC不处理静态资源--> <mvc:default-servlet-handler/> <!-- 支持mvc注解驱动 在spring中一般采用@ResquestMapping注解来完成映射url关系 想要使@RequestMapping注解生效 必须向上下文中注册DefaultAnnotationHandlerMapp 和一个AnnotationMethodHandlerAdpater实例,这两个分别在类级别和方法级别处理 而annotation-driven配置帮助我们自动完成上述两个实例注入 --> <mvc:annotation-driven/> <!--name:访问的映射路径,视图解析器--> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <!--前缀--> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> <!--不使用注解则需要下面的bean注册才能找到对应的url请求地址--> <bean id="/hello" class="fun.nsk666.controller.HelloController"/> </beans
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在对应的包名下新建Controller类
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类名前使用@Controller注解可以返回视图,类上使用@RequestMapping,方法使用@RequestMapping,链接RestFul风格使用请看下文
package fun.nsk666.controller; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.support.RedirectAttributes; @Controller //使用此注解是可以返回视图的 @RequestMapping("hello") //使用此注解:如果想请求下面的方法,则先加hello,比如请求helloAnnotation,则地址为 //Project/hello/helloAnnotation public class HelloAnnotationController { @RequestMapping("helloAnnotation") //此注解是url能匹配到这个方法的注解 public String hello(Model model){ model.addAttribute("msg","helloAnnotation"); return "index"; } @RequestMapping("helloJson/{a}") //RestFul风格,使用@PathVariable注解,参数按照RequestMapping的要求填入 public String helloJson(@PathVariable int a,Model model){ model.addAttribute("msg","helloAnnotation"+a); return "index"; } @RequestMapping("view") public String view( Model model, RedirectAttributes attributes){ model.addAttribute("msg","a+b="); attributes.addAttribute("msg","redirect:a+b="); return "redirect:/test.jsp"; //return的时候 Model对象默认使用的是转发,如果加了 //redirect,则为重定向,注意在WEB-INF文件夹下的jsp页面无法直接访问 } }
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类名前使用@RestController时,此类中的方法返回的都是字符串,无页面跳转,不会被视图解析
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RestFul风格说明
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使用此风格是可以在url中省略参数的‘?’可以用/替代,改变url风格,实现的功能相同
@RequestMapping("hello") public String hello(int a,int b,Model model){ model.addAttribute("msg","helloAnnotation"+(a+b)); return "index"; } //使用上面的方法要想用a和b参数,url要写成/hello?a=1&b=2才可,相对数据不安全 @RequestMapping("hello/{a}/{b}") public String helloJson(@PathVariable int a,@PathVariable int b,Model model){ model.addAttribute("msg","helloAnnotation"+(a+b)); return "index"; } //使用上面的方法url要写成/hello/1/2即可
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@RequestMapping中的参数
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@RequestMapping(value=“请求的地址”)所有请求方式都行
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@RequestMapping(value=“请求的地址”,method=RequestMethod.POST)
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@RequestMapping(value=“请求的地址”,method={RequestMethod.POST,RequestMethod.GET})
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可用不同的提交方式,同一个请求的url实现不同返回结果
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@RequestMapping 如果固定了请求方法可以使用@GetMapping,@PostMapping等
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接收前端的参数
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public String helloJson(@RequestParam(nameuser) String name,Model model) 前端的input签或者参数key的名字只能用nameuser,然后接收后给形参name,否则报错
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public String helloJson(User user,Model model) 可以从前端或者参数中接收与User类中相同的属性,若属性名能对上,则能接收此数据
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数据发送到前端,一般可用ModelAndView、ModelMap、Model,常用Model
@RequestMapping("/random")
public String random(Model model){
Articles a = articleService.getArticleRandom();
System.out.println(a);
model.addAttribute("article",a);
model.addAttribute("msg","test");
return "index";
}